Differences in Adherence and Non-Adherence Behaviour Patterns to Inhaler Devices Between COPD and Asthma Patients.

Differences between COPD and asthma may also differentially affect adherence to inhaled drugs in each disease. We aimed to determine differences in behaviour patterns of adherence and non-adherence to inhaled therapy between patients with COPD and patients with asthma using the Test of Adherence to Inhalers (TAI) questionnaire. A total of 910 patients (55% with asthma, 45% with COPD) participated in a cross-sectional multicentre study. Data recorded included sociodemographics, education level, asthma or COPD history, TAI score, the Asthma Control Test (ACT), the COPD Assessment Test (CAT) and spirometry. Asthma patients were statistically significant less adherents, 140 (28%) vs. 201 (49%), and the pattern of non-adherence was more frequently erratic (66.8% vs. 47.8%) and deliberate (47.2% vs. 34.1%) than COPD patients; however unwitting non-adherence was more frequently observed in COPD group (31.2% vs. 22.8%). Moreover, taking together all sample studied, only being younger than 50 years of age (OR 1.88 [95% CI: 1.26-2.81]) and active working status (OR 1.45 [95% CI: 1.00-2.09]) were risk factors for non-adherence in the multivariate analysis, while having asthma remained in the limits of the significance (OR 1.44 [95%CI: 0.97-2.14]). Even though non-adherence to inhalers is more frequently observed in asthma than in COPD patients and exhibited a different non-adherence patterns, these differences are more likely to be related to sociodemographic characteristics. However, differences in non-adherence patterns should be considered when designing specific education programmes tailored to each disease.

Validation of the 'Test of the Adherence to Inhalers' (TAI) for Asthma and COPD Patients.

BACKGROUND: To validate the 'Test of Adherence to Inhalers' (TAI), a 12-item questionnaire designed to assess the adherence to inhalers in patients with COPD or asthma. METHODS: A total of 1009 patients with asthma or COPD participated in a cross-sectional multicenter study. Patients with electronic adherence ≥80% were defined as adherents. Construct validity, internal validity, and criterion validity were evaluated. Self-reported adherence was compared with the Morisky-Green questionnaire. RESULTS: Factor analysis study demonstrated two factors, factor 1 was coincident with TAI patient domain (items 1 to 10) and factor 2 with TAI health-care professional domain (items 11 and 12). The Cronbach's alpha was 0.860 and the test-retest reliability 0.883. TAI scores correlated with electronic adherence (ρ=0.293, p=0.01). According to the best cut-off for 10 items (score 50, area under the ROC curve 0.7), 569 (62.5%) patients were classified as non-adherents. The non-adherence behavior pattern was: erratic 527 (57.9%), deliberate 375 (41.2%), and unwitting 242 (26.6%) patients. As compared to Morisky-Green test, TAI showed better psychometric properties. CONCLUSIONS: The TAI is a reliable and homogeneous questionnaire to identify easily non-adherence and to classify from a clinical perspective the barriers related to the use of inhalers in asthma and COPD.